Some surgeons have performed anterior cruciate ligament (ACL) surgery using a retrograde approach to create the femoral ACL tunnels (i.e., “All-Inside ACL Reconstruction”). As illustrated in FIG. 1, this approach typically requires a surgical instrument 100 that can drill a tunnel 102 in a retrograde fashion, as the surgeon pulls-back (see directional arrow 108) on the retrograde reamer 104 from a bone joint space 106 towards the lateral femoral cortex. However, such a surgical instrument tends to create a tunnel that is not truly circular, or worse, the tunnel can be created along a pathway that diverges from the intended trajectory, and thus may not be anatomic and/or may cause injury to neurovascular structures, etc. In addition, such a surgical instrument is generally specific for creating tunnels of a certain fixed diameter, which requires having access to a large inventory of instruments for one surgical case.
Moreover, surgeons who conduct ACL reconstruction generally prefer to mimic the natural anatomy to achieve optimal results. The placement of a tendon graft in the original footprint of the ACL is generally referred to as “anatomic ACL reconstruction”. One feature of anatomic ACL reconstruction is the proper placement of the tunnels for the tendon graft. The tunnel exit in the space of the bone joint should be accurate to ensure the functionality of the graft. Further, the tunnel exit on the lateral side of the femur (thigh) should be appropriately placed to ensure adequate tunnel length. It would be desirable to have improved surgical instruments that can assist the surgeon in the proper placement of the femoral tunnel.